JP4832138B2 - In-mold transfer film - Google Patents

Description

  The present invention relates to an in-mold transfer film, and more particularly to an in-mold transfer film useful as a support film for an in-mold transfer foil that is transferred and printed simultaneously with molding in injection molding or the like.

Conventionally, as a transfer foil for in-mold, a polyester film is used as a base film, a release layer (medium layer) is provided thereon, and a print layer is further coated on the release layer.
This in-mold transfer foil is peeled off and separated between the release layer surface and the print layer surface after molding and transfer. That is, after the molding transfer, the printed layer is adhered to the surface of the molded product and taken out as a product, and the release layer is removed from the product while being provided on the base film.

  However, conventional transfer foils for in-mold often have insufficient adhesive force between the release layer and the base film or insufficient release properties between the release layer surface and the print layer surface. In the subsequent peeling treatment, peeling often occurs between the release layer surface and the base film surface, and the release layer remains on the surface of the molded product together with the printing layer. This problem is considered to be caused by peeling of the release layer and the base film due to distortion when the laminated film is deformed in in-mold transfer.

JP-A-6-115295 JP 2004-223800 A JP 2004-174975 A JP 2004-58648 A

  In order to improve this point, it is effective to provide an adhesive layer between the base film and the release layer to improve the adhesion between the base film and the release layer. However, as the resin constituting the adhesive layer, a resin having low solvent resistance is used in order to obtain good adhesive properties. For this reason, when the release layer is applied, the adhesive layer dissolved or softened by the solvent is partially peeled off by the release layer coating tool, and the adhesive strength between the release layer and the base film decreases. A new problem arises. Moreover, the film which laminated | stacked the contact bonding layer has the problem that it is inferior to handling property at the time of providing a release layer on this film, in which films are easy to stick together and is inferior in blocking resistance.

  In recent years, in-mold transfer requires higher productivity, and attempts have been made to improve the molding speed. When handling the in-mold transfer foil, sticking of the transfer foils due to electrification and adhesion of dust and dust to the surface of the transfer foil may occur, which may reduce productivity. In addition, the mold is contaminated with oligomers generated from the polyester film during molding, and the mold is frequently washed, which causes a decrease in productivity.

  Usually, an antistatic agent is applied to the film surface to prevent dust and dirt from adhering to the film. However, a general antistatic agent is an ionic compound and is weak against water. Washing water is used to remove unnecessary materials in processes such as printing of in-mold transfer foil, and the antistatic layer is washed. There is a problem of elution with water.

  The present invention aims to solve the problems of the prior art, has an excellent antistatic property during the process from the in-mold transfer foil preparation process to the molding transfer, and can greatly improve the productivity. In particular, an object of the present invention is to provide an in-mold transfer film that can provide a matte surface appearance and is useful as a base film for an in-mold transfer foil that is excellent in winding property and blocking resistance.

That is, the present invention is an in-mold transfer film comprising a polyester film and an antistatic layer containing a cationic polymer provided thereon, and the centerline average surface roughness Ra of the polyester film is 25 to 50 nm and conforms to JISZ8741. The 60 ° glossiness of the film surface opposite to the antistatic layer measured in the above is 100 to 150 , and the cationic polymer contains a monomer component (a) represented by the following formula as a constituent of the polymer. It is the film for in-mold transfer characterized.

  According to the present invention, it has excellent antistatic properties from the process of creating a transfer foil for in-mold to molding transfer, and can greatly improve the productivity, in particular, to obtain a matte surface appearance. It is possible to provide an in-mold transfer film that is useful as a base film for an in-mold transfer foil excellent in winding property and blocking resistance.

Hereinafter, the present invention will be described in detail.
[Polyester film]
In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of such polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), and polyethylene-2,6-naphthalate.

  The polyester may be a copolymer of these polyesters, and the polyester is the main component (for example, 80 mol% or more) and blended with other kinds of resins in a small proportion (for example, 20 mol% or less). It may be. Polyethylene terephthalate is particularly preferred as the polyester because it has a good balance between mechanical properties and moldability.

  The center line average surface roughness Ra of the polyester film is 20 to 50 nm, preferably 25 to 45 nm. When Ra is less than 20 nm, a good matte appearance cannot be obtained, and good winding properties and blocking resistance cannot be obtained. When Ra exceeds 50 nm, the transparency of the film decreases, and it becomes difficult to inspect the appearance of the printed layer during processing of the in-mold transfer foil. The coating film formed in the present invention has a sufficiently thin center line average surface roughness Ra on the surface of the coating film after the coating film is provided and the center line average surface roughness Ra on the surface of the base polyester film. . Therefore, the center line average surface roughness Ra of the polyester film can be obtained by measuring the center line average surface roughness of the coating film surface in a state where the coating film is provided.

  The polyester film is preferably added with fine particles in order to obtain a matte surface appearance by in-mold molding. When the fine particles are contained, good winding properties can be imparted. As the fine particles, inorganic lubricants and organic lubricants can be used. Examples of inorganic lubricants include silica (including massive, porous, and spherical), titanium oxide, aluminum oxide (particularly the crystal system is γ, δ, θ type), calcium carbonate, and barium sulfate. Examples of the organic lubricant include spherical silicone resin particles and crosslinked polystyrene particles. When using fine particles, one type or two or more types may be used. When using 2 or more types, you may combine what differs in an average particle diameter.

  In order to make the surface roughness Ra of the polyester film 20 to 50 nm, it is preferable that the average particle diameter of the fine particles used is 0.5 to 5.0 μm and the blending amount is 0.02 to 1% by weight. If the average particle size is less than 0.5 μm, sufficient surface roughness cannot be obtained, and the matte surface appearance is not achieved by in-mold molding, and if it exceeds 5.0 μm, the strength of the film is lowered, which is not preferable. . If the amount of fine particles added is less than 0.02% by weight, a sufficient roughness cannot be obtained, and if it exceeds 1% by weight, the transparency is lowered, which is not preferable.

  Since the polyester film may confirm the state by observing the printed layer of the transfer foil for in-mold from the opposite side, it is preferable that the polyester film has high transparency. The polyester film may contain, for example, a colorant, an antistatic agent, and an antioxidant.

  The polyester film can be produced, for example, by the following method. That is, polyester is melt-extruded into a film, cooled and solidified with a casting drum to form an amorphous unstretched film, and stretched in the machine and transverse directions. Stretching in the machine direction is, for example, at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., and stretched in the machine direction of, for example, 2.0 to 4.0 times, preferably 2.5 to 3.5 times. Stretching in the transverse direction is, for example, at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C., and stretched in the transverse direction, for example, 2.0 to 4.0 times, preferably 3.0 to 4.0 times. The area magnification after biaxial stretching is preferably 13 or less.

  In addition, it is preferable to perform a heat setting process after extending | stretching a film. The heat setting treatment is preferably performed within a time period of 1 to 30 seconds within a temperature higher than the final stretching temperature and not higher than the melting point. For example, in the case of a polyethylene terephthalate film, it is preferable to select and heat-set at a temperature of 150 to 250 ° C. and a time of 2 to 30 seconds. At that time, it may be performed under a limited contraction or expansion within 20%, or under a constant length, or may be performed in two or more stages.

  The thickness of the polyester film is preferably 12 to 100 μm, and more preferably 25 to 75 μm, in order to obtain necessary strength from the viewpoints of handling properties, moldability and transparency when used as in-mold transfer.

[Antistatic layer]
[Cationic polymer]
In the present invention, the antistatic layer contains a cationic polymer. This cationic polymer contains a monomer component (a) represented by the following formula as a constituent component of the polymer.

R ¹ and R ² are each a saturated hydrocarbon group having 1 to 3 carbon atoms, specifically a methyl group, an ethyl group, or a propyl group. R ³ is an alkylene group having 1 to 10 carbon atoms, such as an ethylene group, a trimethylene group, or a tetramethylene group. R ⁴ and R ⁵ are each a saturated hydrocarbon group having 1 to 3 carbon atoms, specifically a methyl group, an ethyl group, or a propyl group. R ⁶ is a hydroxyalkylene group having 2 to 4 carbon atoms, for example, a hydroxyethylene group, a hydroxytrimethylene group, or a hydroxytetramethylene group. Y < ^- > is an alkyl sulfonate having 1 to 3 carbon atoms, fluorine, chlorine, bromine or iodine ions. Specific examples of the alkyl sulfonate having 1 to 3 carbon atoms include methyl sulfonate, ethyl sulfonate, and propyl sulfonate.

The monomer component (a) is preferably used in the range of 30 to 79 mol% per 100 mol% of the monomer component constituting the cationic polymer. If it is less than 30 mol%, the antistatic property becomes undesirably higher than 1 × 10 ¹³ Ω / □. If it exceeds 79 mol%, the water resistance of the coating film becomes poor and the antistatic property after washing with water is lowered, which is not preferable.

The cationic polymer preferably contains a monomer component (a), a non-reactive monomer component (b), and a reactive monomer component (c) as constituent components of the polymer. In this case, the composition ratio of each component preferably satisfies the following formula.
30 mol% ≦ a ≦ 79 mol%
20 mol% ≦ b ≦ 100− (a + c) mol%
1 mol% ≦ c ≦ 40 mol%
When the cationic polymer is composed of components that satisfy these conditions, it is possible to obtain a coating film that has excellent film-forming properties, cohesive strength, water resistance of the coating film, and chemical resistance.

  As the non-reacting monomer component (b), alkyl acrylate, alkyl methacrylate (alkyl groups include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2 -Ethylhexyl group, cyclohexyl group), styrene, and α-methylstyrene.

  The non-reactive monomer component (b) is preferably used in the range of 20 to 70 mol% per 100 mol% of the monomer component constituting the cationic polymer. If it is less than 20 mol%, the adhesion to the polyester film and the cohesiveness of the coating film become low, which is not preferable. When it exceeds 70 mol, the antistatic property is lowered, which is not preferable.

  Examples of the reactive monomer component (c) include hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate; glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and the like. Epoxy group-containing monomers; carboxy groups such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.) Or a monomer containing a salt thereof; acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N-dialkylacrylamide, N, N-dialkylmeta Relate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.), N-alkoxyacrylamide, N -Alkoxymethacrylamide, N, N-dialkoxyacrylamide, N, N-dialkoxymethacrylamide (alkoxy groups include methoxy, ethoxy, butoxy, isobutoxy, etc.), acryloylmorpholine, N-methylolacrylamide, N -Monomers containing amide groups such as methylol methacrylamide, N-phenyl acrylamide, N-phenyl methacrylamide; monomers of acid anhydrides such as maleic anhydride and itaconic anhydride; Isocyanates such as vinyl isocyanate and allyl isocyanate It can be exemplified over preparative-containing monomer.

  The reactive monomer component (c) is preferably used in the range of 1 to 40 mol% per 100 mol% of the monomer component constituting the cationic polymer. If it is less than 1 mol%, the antistatic property of water resistance is lowered, and the surface resistivity change rate after immersion for 10 hours at 50 ° C. in hot water exceeds 100, such being undesirable. If it exceeds 40 mol%, the number of cross-linking points increases and the film forming property of the coating film deteriorates, which is not preferable.

[Fine particles]
It is preferable that fine particles are contained in the antistatic layer. When the fine particles are contained, those having an average particle diameter of 20 to 100 nm, more preferably 40 to 80 nm are preferably used. When the film is less than 20 nm, the blocking property and the film winding property when the film is wound are inferior, and furthermore, in the form of the in-mold transfer foil, the antistatic layer is in contact with the printing layer, but at this time, the antistatic layer and the printing are printed. Layer blocking may occur, which is not preferable. If it exceeds 100 nm, omission of fine particles and transparency of the coating layer may be deteriorated, which is not preferable.

  The fine particles are preferably contained in the antistatic layer in an amount of 5 to 30% by weight. If it is less than 5% by weight, blocking of the antistatic layer and the printed layer may occur in the form of the in-mold transfer foil, which is not preferable. If it exceeds 30% by weight, fine particles may be lost from the coating layer, which is not preferable.

  As the fine particles, either inorganic fine particles or organic fine particles can be used. Examples of the inorganic fine particles include silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, titanium oxide, zinc oxide, barium sulfate, zirconium oxide, titanium oxide, tin oxide, antimony trioxide, carbon black, molybdenum disulfide. Particles consisting of can be used. As the organic fine particles, for example, organic fine particles made of a heat-resistant resin such as an acrylic cross-linked polymer, a styrene cross-linked polymer, a silicone resin, a fluororesin, a benzoguanamine resin, a phenol resin, and a nylon resin can be used.

[Crosslinking agent]
It is preferable that the antistatic layer further contains a crosslinking agent in order to improve the cohesive strength of the coating film and to suppress the precipitated oligomers during heating. As a crosslinking agent, an epoxy compound, an oxazoline compound, a melamine compound, an isocyanate compound can be illustrated, and another coupling agent can also be used. Epoxy compounds and oxazoline compounds are preferably used because of easy handling and the pot life of the coating liquid, and a coupling agent is also preferably used.

Specific examples of the crosslinking agent are as follows.
Examples of the epoxy compound include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, etc. Examples of the polyepoxy compounds include sorbitol, polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diester. Glycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diepoxy compounds include, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl Ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol As diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, monoepoxy compound, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, glycidyl amine compound N, N, N ′, N ′,-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

  The oxazoline compound is a compound having an oxazoline group, and a polymer is preferably used. For example, the addition-polymerizable oxazoline group-containing monomer can be polymerized alone or can be produced by copolymerization with other monomers. As addition-polymerizable oxazoline group-containing monomers, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. As the other monomer, a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer is used. For example, alkyl acrylate, alkyl methacrylate (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group). (Meth) acrylic acid esters such as acetyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid And unsaturated carboxylic acids such as salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide, N -Alkyl methacrylamide, N, N Dialkyl acrylamide, N, N-dialkyl methacrylate (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc. ); Vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; vinyl chloride, vinylidene chloride, vinyl fluoride, etc. Halogen-containing α, β-unsaturated monomers: α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, etc., and one or more of these monomers should be used Can do.

As the melamine compound, it is preferable to use a compound obtained by reacting a lower alcohol with a methylolmelamine derivative obtained by condensing melamine and formaldehyde.
Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. As the lower alcohol, for example, an alcohol having 1 to 3 carbon atoms, specifically methyl alcohol, ethyl alcohol, or isopropyl alcohol is used.

  Isocyanate compounds include, for example, tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, an adduct of tolylene diisocyanate and hexane triol, Tolylene diisocyanate and trimethylolpropane adduct, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-vitrylene- Examples include 4,4 'diisocyanate, 3,3' dimethyldiphenylmethane-4,4'-diisocyanate, and metaphenylene diisocyanate. .

For example, a silane coupling agent can be used as the coupling agent. This is a compound represented by the general formula YRSiX _3. Here, Y is an organic functional group such as vinyl group, epoxy group, amino group, and mercapto group, R is an alkylene group such as methylene, ethylene, and propylene group, and X is a hydrolyzable group such as methoxy group and ethoxy group, and an alkyl group. It is particularly preferred that the Y moiety is an epoxy group.

  Preferred silane coupling agents are γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane.

  As the coupling agent, an organometallic compound containing a metal such as zirconium, titanium, or aluminum can be used. For example, those classified into alkoxides, chelates, and acylates are preferable. Specifically, zirconium tetraacetylacetonate, zirconium acetate, titanium acetylacetonate, triethanolamine titanate, and titanium lactate can be exemplified.

  When a crosslinking agent is used, the amount of crosslinking agent added is preferably 5 to 50% by weight per 100% by weight of the total weight of the antistatic layer. If it is less than 5% by weight, the cohesive force of the coating layer is lowered, and the durability may be deteriorated. If it exceeds 50% by weight, the film forming property of the coating layer is deteriorated, and the coating appearance is deteriorated.

  In the present invention, the antistatic layer is preferably provided on the polyester film by coating. The thickness of the antistatic layer is preferably 0.01 to 0.1 [mu] m, more preferably 0.01 to 0.06 [mu] m, as the thickness after drying. If it is less than 0.01 μm, the antistatic property becomes insufficient, which is not preferable, and if it exceeds 0.1 μm, blocking with the in-mold transfer foil is likely to occur.

[Surface specific resistance]
The surface specific resistance of the antistatic layer is preferably 1 × 10 ¹³ Ω / □ or less, more preferably 1 × 10 ¹² / □ or less. When the surface resistivity exceeds 1 × 10 ¹³ Ω / □, the antistatic property required in the present invention cannot be obtained, which is not preferable. Further, the surface resistivity change rate of the surface of the antistatic coating layer after being immersed in warm water at 50 ° C. for 10 hours is preferably 100 or less, more preferably 10 or less. The rate of change of the surface resistivity is a value obtained by dividing the surface resistivity of the surface of the antistatic layer after being immersed in pure water at 50 ° C. for 10 hours by the surface resistivity of the surface of the untreated antistatic layer. is there. If the surface resistivity change rate exceeds 100, the antistatic layer may be eluted when unnecessary substances are removed using washing water in a process such as printing of the in-mold transfer foil, which is not preferable.

[Easily adhesive layer]
In the present invention, it is preferable that an easy adhesion layer is provided on the side of the polyester film opposite to the antistatic layer. The easy adhesion layer is preferably an easy adhesion coating layer provided by coating. For the easy adhesion layer, it is preferable to use a copolymerized polyester in order to obtain high adhesion to a release layer provided when used as an in-mold transfer foil.

  As the copolyester, for example, a polyester obtained from the following polybasic acid component and diol component can be used. That is, as the polyvalent base component, for example, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, Examples include pyromellitic acid, dimer acid, and 5-sodium sulfoisophthalic acid. As the polyester resin constituting the polymer binder, it is preferable to use a copolymerized polyester using two or more kinds of dicarboxylic acid components. The polyester may contain an unsaturated polybasic acid component such as maleic acid or itaconic acid, or a hydroxycarboxylic acid component such as p-hydroxybenzoic acid, if it is in a slight amount. Polyester diol components include ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, and the like, poly (ethylene oxide) ) Glycol and poly (tetramethylene oxide) glycol.

  The copolyester preferably has a glass transition point (Tg) of 40 to 85 ° C, more preferably 45 to 80 ° C. A film obtained when the Tg of the copolyester is less than 40 ° C. is not preferable because the heat resistance and blocking resistance are inferior, and if it exceeds 85 ° C., the easy adhesion property is not preferable.

  The copolymerized polyester is preferably used in the form of an aqueous dispersion or an emulsion to form a coating layer. In order to form a coating layer, other resins, colorants, antistatic agents, catalysts, stabilizers, surfactants, antioxidants, ultraviolet absorbers and the like may be included as necessary in addition to the copolymer polyester. You can also.

[Fine particles]
The easy adhesion layer preferably contains fine particles. As the fine particles, those having an average particle diameter of 20 to 100 nm, more preferably 40 to 80 nm are used. When the average particle size is less than 20 nm, the blocking property and the film winding property when the film is wound are inferior, which is not preferable. When the average particle size is more than 100 nm, the lack of fine particles and the transparency of the coating layer may be deteriorated.

  When using fine particles, it is preferably used at a ratio of 30% by weight or less per 100% by weight of the easy-adhesion layer. If it exceeds 30% by weight, the strength of the coating layer is lowered, and troubles such as coating film scraping occur in the subsequent steps, which is not preferable.

  Examples of the fine particles include silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, titanium oxide, zinc oxide, barium sulfate, zirconium oxide, titanium oxide, tin oxide, antimony trioxide, carbon black, and molybdenum disulfide. Examples of the organic fine particles include heat-resistant resins such as inorganic fine particles, acrylic cross-linked polymers, styrene cross-linked polymers, silicone resins, fluororesins, benzoguanamine resins, phenol resins, and nylon resins. Among these, silicon oxide, cross-linked polystyrene resin particles, and cross-linked acrylic resin particles are preferable from the viewpoint of handling and stability in the coating liquid and dispersibility in the coating film.

  The thickness of the easy adhesion layer is preferably 0.05 to 0.3 μm, and more preferably 0.07 to 0.2 μm, as the final thickness after drying. If the thickness is less than 0.05 μm, the adhesiveness becomes insufficient, which is not preferable, and if it exceeds 0.3 μm, blocking tends to occur, which is not preferable.

[Production method]
In the present invention, the composition used for coating the antistatic layer and the easy-adhesion layer may be used in the form of an aqueous coating liquid, for example, an aqueous solution, an aqueous dispersion or an emulsion to form a coating layer. preferable. In order to form a coating film, other resins other than the above-described composition, for example, a colorant, a surfactant, and an ultraviolet absorber may be added as necessary.

  The solid content concentration of the aqueous coating liquid used in the present invention is usually 20% by weight or less, preferably 1 to 10% by weight. If it is less than 1% by weight, the coating properties on the polyester film may be insufficient, and if it exceeds 20% by weight, the stability of the coating liquid and the appearance of the coating layer may be deteriorated.

  Application of the aqueous coating solution to the polyester film can be carried out at any stage, but it is preferably carried out during the production process of the polyester film, and is further applied to the polyester film before the completion of orientational crystallization. Is preferred.

  Here, the polyester film before the completion of crystal orientation is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. It includes those that have been stretched and oriented at a low magnification (biaxially stretched film before being finally re-stretched in the machine direction or the transverse direction to complete orientation crystallization). In particular, it is preferable to apply the aqueous coating liquid of the above composition to an unstretched film or a uniaxially stretched film oriented in one direction, and perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  When applying an aqueous coating liquid to a film, as a pretreatment for improving the coating property, the film surface is subjected to physical treatment such as corona surface treatment, flame treatment, plasma treatment, etc., or chemically combined with the composition. It is preferable to use an inert surfactant in combination.

  Such a surfactant acts to promote the wetting of the aqueous coating liquid on the polyester film and to improve the stability of the coating liquid. For example, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal Anionic and nonionic surfactants such as soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates can be mentioned. The surfactant is preferably contained in an amount of 1 to 10% by weight in the composition forming the coating film.

  As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination.

  Hereinafter, the present invention will be described in more detail with reference to examples. Various physical properties were evaluated by the following methods.

(1) Adhesiveness of antistatic layer The surface of the antistatic layer of the film was rubbed with a finger 10 cm long for 10 reciprocations, the missing state of the coating film was observed, and the antistatic layer adhesion was evaluated according to the following criteria.
A: No change A: Some change on the surface B: Half of the scratched area is missing C: Most of the scratched area is missing

(2) Antistatic property / surface specific resistance value The surface specific resistance of the antistatic layer surface of the sample film was measured using a specific resistance measuring instrument manufactured by Takeda Riken Co., Ltd. under the conditions of a measurement temperature of 23 ° C. and a measurement humidity of 60%. The surface specific resistance value (Ω / □) after 1 minute at an applied voltage of 100 V was measured.
-Change rate of surface specific resistance value The surface specific resistance value of the surface of the antistatic layer after the sample film was immersed in pure water at 50 ° C for 10 hours was measured in the same manner as described above, and the untreated surface specific resistance value and 50 ° C The change rate of the surface resistivity after 10 hours of immersion in pure water was determined. The rate of change of the surface specific resistance value is a value obtained by dividing the surface specific resistance value of the surface of the antistatic layer after being immersed in pure water at 50 ° C. for 10 hours by the surface specific resistance value of the surface of the untreated antistatic layer. is there.

(3) Blocking resistance In order to evaluate the blocking resistance between the antistatic layer surface of the sample film and the printing surface of the in-mold transfer foil, a stamping foil pigment foil (COLORIT) P type (manufactured by Kurz) is used. The antistatic surface and the printing surface are combined, and the temperature is 60 ° C., the pressure is 1 kg / cm ^2, and the environment is maintained for 24 hours. Then, the blocking state between the antistatic layer surface and the label seal surface is observed. evaluated. In this evaluation, up to A satisfies practical performance.
A: No change A: Some change on the surface B: Partially peeled C: Fully peeled

(4) Release layer adhesiveness A 1 μm-thick release layer (medium layer) film is formed by applying a methyl ethyl ketone / toluene solution of melamine resin on the coating surface of the film, and gold as a laminate by hot pressing. The state of the release layer when it was molded on the mold was observed and evaluated according to the following criteria. In this evaluation, up to A satisfies practical performance.
A: No change B: Partially peeled C: Whole peeled

(5) Coating layer thickness The film is fixed with an embedding resin, the cross section is cut with a microtome, stained with 2% osmic acid at 60 ° C. for 2 hours, and coated using a transmission electron microscope (JEM2010, manufactured by JEOL Ltd.). The layer thickness was measured.

(6) Matte appearance According to JIS Z8741, the glossiness of 60 ° was measured on the in-mold transfer foil processed surface of the film with a gloss meter (GM-268 manufactured by Minolta). However, black tape was applied to the surface opposite to the measurement surface to prevent reflection on the back surface. By measuring the glossiness of the film surface, the matte degree of the surface of the molded body after in-mold molding can be evaluated. When the glossiness of the film surface is in the range of 100 to 150, an appropriate matte appearance is obtained. In addition, when the glossiness is higher than 150, the surface of the molded body is not preferable because it becomes a mirror surface, and when it is less than 100, the surface of the molded body is too rough.

(7) Coefficient of Friction According to ASTM D1894-63, use a slippery measuring instrument manufactured by Toyo Tester Co. The static friction coefficient (μs) with the surface was measured. However, the thread plate was a glass plate and the load was 1 kg. In this evaluation, up to A satisfies practical performance.
A +: Friction coefficient (μs) ≦ 0.3 …… Excellent slipperiness A: 0.3 <Friction coefficient (μs) ≦ 0.5 …… Good slipperiness B: 0.5 <Friction coefficient (μs) ≦ 0 .8 …… Slightly poor slipping C: 0.8 <Friction coefficient (μs) …… Slippery failure

(8) Centerline average surface roughness (Ra)
In accordance with JIS B0601, using a high-precision surface roughness meter SE-3FAT manufactured by Kosaka Laboratory, under the conditions of a needle radius of 2 μm, load of 30 mg, magnification of 200,000 times, and cutoff of 0.08 mm A chart is drawn, and the portion of the measurement length L is extracted from the surface roughness curve in the direction of the center line. The center line of the extracted portion is the X axis, the direction of the vertical magnification and the Y axis, and the roughness curve is Y = f When represented by (x), the value given by the following equation was expressed in nm. In this measurement, four pieces were measured with a reference length of 1.25 mm and expressed as an average value.

[Examples 1 and 2]
Molten polyethylene terephthalate ([η] = 0.64 dl / g, Tg = 78 ° C.) containing 0.1 wt% of silicon oxide fine particles having an average particle diameter of 2 μm is extruded from a die and cooled by a cooling drum by a conventional method. After unstretched film and then stretched by a factor of 3.4 in the machine direction, each coating solution consisting of the coating layer constituents shown in the table (easy-adhesive layer: 5 wt%, antistatic layer: 3 wt%) is uniformly applied by a roll coater. It was applied to. The coated film was subsequently dried at 105 ° C., stretched 3.5 times at 140 ° C., and heat-set at 230 ° C. to obtain a biaxially stretched polyester film (thickness 38 μm) having the coating film shown in the table. It was.

These Examples 1 and 2 can obtain a matte appearance on the surface of the in-mold molded body, and are excellent in film winding property, blocking resistance with a transfer foil, and adhesion with a release layer at the time of molding. It was possible to obtain as a base film of a transfer foil for in-mold.
The centerline average surface roughness Ra of the polyester film was the centerline average surface roughness Ra obtained by measuring the polyester film prepared in Comparative Example 2 without providing the coating layer.

[Comparative Example 1]
A coated film was obtained in the same manner as in Example 1 except that the amount of fine particles of silicon oxide having an average particle diameter of 2 μm in the film contained 0.01 wt%.

[Comparative Example 2]
A coated film was obtained in the same manner as in Example 1 except that the coating layer was not provided.

In the table, the components used are as follows.
Cationic polymer 1:
A structure represented by the following formula is a copolymer composed of 85 mol% / methyl acrylate 10 mol% / N-methylol acrylamide 5 mol%.

Cationic polymer 2:
A structure represented by the following formula is a copolymer composed of 70% by mole / 25% by mole of methyl acrylate / 5% by mole of acrylic acid.

Cross-linking agent:
Oxazoline (trade name EPOCROSS WS-700 manufactured by Nippon Shokubai Co., Ltd.)
Surfactant:
Polyoxyethylene (n = 8.5) lauryl ether (trade name NAROACTY N-85, manufactured by Sanyo Chemical Co., Ltd.).

Copolyester:
The acid component is composed of 50 mol% terephthalic acid / 45 mol% isophthalic acid / 5 mol% 5-sodium sulfoisophthalic acid, and the glycol component is composed of 90 mol% ethylene glycol / 10 mol% diethylene glycol (Tg = 40 ° C.). In addition, polyester was manufactured as follows according to the method of Example 1 of Unexamined-Japanese-Patent No. 06-116487. That is, 30 parts of dimethyl terephthalate, 27 parts of dimethyl isophthalate, 5 parts of dimethyl 5-sodiumsulfoisophthalate, 36 parts of ethylene glycol and 3 parts of diethylene glycol were charged into the reactor, and 0.05 part of tetrabutoxy titanium was added thereto. Then, the temperature was controlled at 230 ° C. in a nitrogen atmosphere, and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C., and the inside of the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a copolyester.

  The in-mold transfer film of the present invention can be suitably used for in-mold molding that exhibits a matte appearance.

Claims (5)

An anti-mold film comprising an antistatic layer containing a polyester film and a cationic polymer provided thereon, the antistatic layer having a center line average surface roughness Ra of 25 to 50 nm and measured according to JISZ8741 An in-mold characterized in that the film surface on the side opposite to the layer has a 60 ° gloss of 100 to 150 , and the cationic polymer contains a monomer component (a) represented by the following formula as a constituent of the polymer: Transfer film.

The cationic polymer comprises the monomer component (a), the non-reactive monomer component (b), and the reactive monomer component (c) as constituent components of the polymer, and the composition ratio of each component satisfies the following formula. In-mold transfer film.
30 mol% ≦ a ≦ 79 mol%
20 mol% ≦ b ≦ 100− (a + c) mol%
1 mol% ≦ c ≦ 40 mol%   The in-mold transfer film according to claim 1, wherein the antistatic layer further contains a crosslinking agent. The surface resistivity of the antistatic layer is 1 × 10 ¹³ Ω / □ or less, and the surface resistivity change rate of the surface of the antistatic coating layer after being immersed in hot water at 50 ° C. for 10 hours is 100 or less. Item 2. The in-mold transfer film according to Item 1.   The in-mold transfer film according to claim 1, wherein an easy-adhesion layer is provided on the side opposite to the antistatic layer of the polyester film.